Embodiments of the present disclosure relate to the field of semiconductor manufacturing technology, and in particular to wafer bonding method.
Wafer bonding is deployed in a wide range of semiconductor process applications for forming semiconductor devices. There are a number of wafer bonding methods, including adhesive boding, anodic bonding, direct wafer bonding, metal bonding, and hybrid metal/dielectric bonding.
Direct wafer bonding refers to a process where two separate wafer surfaces are brought into contact and are bonded without any intermediate adhesives or external force. Currently direct wafer bonding has many applications in the microelectronics industry. Examples of semiconductor process applications include substrate engineering, fabrication of integrated circuits, packaging and encapsulation of micro-electromechanical-systems (MEMS) and stacking of many processed layers (3D-integration) of pure microelectronics. These different applications require usually more than just a typical silicon wafer bonding process (wafer contacting and annealing at 1100° C.). Bonding of processed wafers or wafers with a large difference in thermal expansion coefficients requires a low-temperature bonding process.